Eccentric adapter for a stuffing box



May 6, 1969 l. GLASSCOCK, JR., ET AL ECCENTRIC ADAPTER FOR A STUFFING BOX Filed July 24, 1967 INVENTO IRA GLASSCOCK JR. Rs

| w|s J. BUNDfiANT MARCUS L. BATES United States Patent 3,442,538 ECCENTRIC ADAPTER FOR A STUFFING BOX Ira Glasscock, Jr., 1005 E. 4th, Big Lake, Tex. 76932, and Lewis J. Bundrant, Box 221, Lubbock, Tex. 79408 Filed July 24, 1967, Ser. No. 655,595 Int. Cl. F161 55/00; F16c I/24 US. Cl. 285178 8 Claims ABSTRACT OF THE DISCLOSURE An eccentric coupling device for aligning a polish rod with a stufiing box of an oil well wherein the eccentric coupling is between the tubing of the oil well and the stufiing box, where by relative rotation between the eccentric coupling and the stuifing box with respect to the tubing, provides alignment between the upper portion of the stufiing box and the reciprocating polish rod. The device rfurther comprehends a template which enables rapid alignment of the stuffing box with the reciprocating polish rod.

BACKGROUND Some oil wells require a pump to be positioned far below the surface of the earth in order to force petroleurn products to flow from an oil strata to a gathering system located above the ground. The down-hole pump requires a reciprocating polish rod which actuates the pump. The reciprocating polish rod is generally actuated by a large motor driven pump-jack unit which usually is mount-ed upon a concrete platform adjacent the upstanding tubing of the oil well. The top of the producing tubing is provided with a stufling box which reciprocatingly receives the polish rod while acting as a seal to prevent oil from flowing out of the stufling box. Accordingly, slight misalignment of the polish rod with the stufling box allows one side of the rod to bear against the stuffing box with unequal forces to thereby cause rapid wear of the rod and box at the point of contact.

Stufling boxes and alignment means therefor are known in the prior art. These prior art alignment means generally involve complicated co-acting parts that are expensive and difficult to fabricate. Furthermore, some of the stuffing boxes of the prior art require expensive maintance inasmuch as the multiplicity of parts required therefor develop leaks and permits the oil to contaminate the area adjacent the well head.

SUMMARY The present invention provides an alignment means that can be used with existing stufiing boxes by merely interposing two eccentric couplings in series between the upper terminal end of the production tubing and the existing stuffing box. The two alignment means are identical in construction and are each comprised of upper and lower threads that are radially displaced from one another to thereby form a double eccentric means whereby the upper threads have a center point which describes a circle about the center point of the lower threads when the eccentric coupling is rotated, or vice versa. By providing an existing stufling box with two eccentric couplings, it is therefore possible to cause the stufiing box to describe two different circles upon rotation of each individual coupling, whereupon the stufling box may be positioned in any desired location within the area provided by the eccentricity of the two eccentric couplings.

Another embodiment of the present invention contem plates the use of an eccentric stufling box in conjunction with one of the before mentioned couplings, thereby eliminating the necessity of providing two identical eccen-- tric couplings in order to attain alignment of the stufling box with the polish rod.

A still further embodiment of the present invention contemplates the provision of an eccentric stufiing box having a lower depending threaded male end that cooperates with an eccentric coupling having upper and lower female threaded terminal end portions to thereby enable the stuffing box to be directly attached to the coupling placed on the upstanding terminal end of a production tubing, thereby advantageously eliminating the necessity of interposing two individual couplings between the stufling box and the upper terminal end of the tubing. The eccentricity provided by the stutfing box and the coupling enables positioning the stufiing box within the limitations provided by the combined eccentricity of the box and coupling to thereby perfectly align the box with the polish rod.

A still further embodiment of the present invention includes the provision of an alignment template having a downwardly depending flange about the outer marginal edge portion thereof to thereby enable the stufiing box to be exactly aligned with the polish rod by merely temporarily substituting the template for the packing nut of the box.

It is therefore an object of the present invention to provide two eccentric couplings that may be interposed in series relationship between a conventional stufling box and the upstanding terminal end of a production tubing to thereby enable the stufling box to be precisely aligned with a polish rod.

Another object of the present invention is the provision of a stufiing box and coupling arrangement which may be screw fitted together and wherein the screw threads are eccentrically placed with respect to each other to thereby cause the stuffing box to be axially displaced when the box and coupling member are rotated with respect to each other and to the tubing to which they are connected.

A still further object of this invention is the provision of an alignment means that can be used in conjunction with a conventional stuffing box to thereby provide a means by which the box can be exactly aligned with respect to a polish rod.

Another object of the present invention is the provision of an alignment means by which stufling boxes can be precisely aligned with respect to a polish rod.

The above objects are attained in accordance with the present invention by the provision of an eccentric thread associated with a stufiing box and an eccentric coupling associated with the upper terminal end of a production tubing wherein relative rotation between the box, coupling, and tubing causes the box to move within an area determined by the amount of eccentricity imparted to the coupling associated with the box, and the coupling associated with the production tubing.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view showing a first embodiment of the invention;

FIGURE 2 is a perspective view showing a second embodiment of the invention;

FIGURE 3 is a partial cross-sectional view taken longitudinally along the embodiment illustrated in FIGURE 1;

FIGURE 4 is a partial cross-sectional view illustrating a still further embodiment of the invention;

FIGURE 5 is a top plan view of an alignment device that is used in conjunction with the embodiments of either of the foregoing figures;

FIGURE 6 is a cross-sectional view taken along line 66 of FIGURE 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Looking now to the details of the drawings, and in particular to FIGURE 1, wherein there is disclosed the present invention and its operative relationship with an oil well. The arrow at numeral 14 indicates a conventional stuffing box which is screw threaded into an eccentric coupling 16 which in turn is screw threaded into a similar eccentric coupling 18 which in turn is aflixed to the upstanding casing 20 of an oil well by means of a conventional coupling 22.

The stufiing box is provided with a conventional cap 24 which is suitably apertured at 26 for receiving a polish rod which extends through the aperture and into the casing in order to actuate a down-hole pump located below the surface of the ground. Numeral 28 indicates the top portion of the eccentric coupling 16 which receives the before mentioned stuffing box 14. Numeral 30 indicates the upper portion of eccentric 18 which receives the eccentric coupling 16. Numeral 32 indicates the upper portion of a standard coupling 22 which receives the eccentric 18. Numeral 34 indicates the lower portion of coupling 22 which is screw fitted onto the upstanding tubing 20.

Looking now to the details of FIGURE 3 in conjunction with the remaining figures, wherein there is illustrated in greater detail the relationship between the conventional stufiing box 14 and the first eccentric coupling 16. It should be understood that the eccentric couplings 16 and 18 are identical in construction, and accordingly, the description will be limited to the single eccentric coupling 16. The stufiing box 14 is provided with male threads 36 which are threadedly received by female threads 38 provided about the upper inside peripheral wall surface of the eccentric coupling 16. At the lower extremity of the coupling there is provided male threads 40 which threadedly engage the upper inside threads of the second coupling member 18, as seen at numeral 30, in a manner similar to the cooperation between the threads of stufiing box 14 and eccentric 16. The eccentric is offset in a radial direction in the area generally illustrated by the arrow at numeral 42 so as to enable the axial center line of the threads 40 to be radially displaced in an eccentric manner from the longitudinally extending center line of the stufiing box 14, as well as any member to which the eccentric may be attached at the lower threaded end 40. The inside diameter 44 of the eccentric 16 is equivalent to the outside diameter of the polish rod plus the amount of eccentricity provided by the offset 42, so as to prevent the polish rod from scrubbing the side wall 44.

The inside diameter 46 of the stufiing box 14 is of a suitable size to contain the packing 48, with the packing 48 being held in compressed relationship between the inside wall 46, the polish rod, and the remainder of the stuffing box components. Suitably disposed at the lower extremity of the stuffing box is an annular ring 50 rigidly attached to the wall 46 by the illustrated welding at numeral 52. A removable ring 54 is forced into abutting relationship with the fixed ring 50 and the slidable packing member 56 is disposed in the usual manner at the upper extremity of the stufiing box to compress the packing 48 as the packing nut 24 is tightened. The packing nut is provided with threads 60 in the usual manner.

Looking now to the details of FIGURE 2, wherein there is illustrated a stuffing box 62 made into an eccentric configuration and screw threaded into an eccentric coupling 64. The eccentric coupling 64 is preferably identical to the before described couplings 16 and 18 of FIG- URES 1 and 3. A packing nut 66, identical in construction to the before described packing nut 24, is suitably disposed at the upper extremity of the eccentric stuffing box 62. The arrow at numeral 68 indicates the offset portion of the stufiing box which imparts the desired amount of eccentricity thereto. The stuffing box 62 is threadedly received at the upper extremity 70 of the before mentioned eccentric coupling 64. The eccentric coupling 64 is provided with eccentricity in the general area indicated by the arrow at numeral 72. Numeral 74 indicates the upper extremity of a standard coupling 22. Numerals 22, 20', and -34 correspond generally to the like or corresponding numerals of FIGURE 1.

FIGURE 4 illustrates still another embodiment of the present invention wherein there is seen a coupling 80, which is identical to the coupling 14 except for the ec centrically cut threads 82. The inside peripheral surface 84 of the coupling is provided with the before mentioned ring and packing nut, such as described in conjunction with FIGURE 3. The central longitudinal axis 83 of the stuffing box 80 is offset with respect to the axially disposed center line of the threads 82. The stufling box 80 is screw threaded into a coupling 85. The coupling 85 has an outside surface 86, upper eccentric threads 87, lower eccentric threads 88, with the eccentric threads being located with respect to each other to thereby provide a center line with respect to the threads 87, and a center line 91 with respect to the threads 88. Accordingly, as the stufiing box '80 is rotated with respect to threads 87, the center line 83 thereof describes a circle about the center line 90. When the coupling 85 is affixed to the top of the casing 20, rotation thereof causes the center line 91 of threads 88 to describe a circle about the center line of the casing 20. Accordingly, the stuffing box 80' can be exactly aligned with a polish rod by rotating coupling 80 with respect to coupling 85, and by rotating coupling 85 with respect to the casing 20 to thereby align the polish rod with respect to the stuffing box 80, so long as the amount of misalignment does not exceed the amount of eccentricity provided by the stufiing box 80 and the coupling 85 FIGURES 5 and 6 illustrate a split circular alignment member 92 that includes a first semicircular member 93 and a second semicircular member 94 that provides a waffer-like flanged member when joined together along edge portions 95 and 96. The inside aperture 97 is substantially equal to the outside diameter of the polish rod. .Downwardly depending flange member 98 has an outside diameter substantially equal to the inside diameter 46, for example, of the stufiing box 14. The outwardly depending marginal edge portion 99 is adapted to rest upon the upper terminal end portion of a stuffing box 14, for example.

OPERATION In carrying out the invention in accordance with the operation of the embodiment of FIGURE 1, the stuffing box 14 is connected to the upstanding terminal end of a well casing 20 by means of the interposed coupling members 16, 18, and 22. All of the members; including the standard coupling 22, the standard stuffing box 14, and the eccentric couplings 16 and 18; are fitted together by means of screw threaded connections whereupon one member is rotatably movable with respect to another member. Since the large pump jack unit (not shown) that reciprocates the polish rod (not shown) is extremely heavy and difiicult to move, exact alignment between the stuffing box 14 and the polish rod is difficult to achieve. Consequently, there is generally a slight amount of misalignment between the polish rod and a conventional stufiing box which causes the polish rod to bear against the stuffing box on one side, dependent upon the 7 direction and magnitude of the misalignment. Therefore,

by rotating the two interposed eccentric coupling members, 16 and 18 of the instant invention, the slight misalignment that normally exists between the stufiing box and the polish rod can be eliminated, so long as the eccentricity provided by the two eccentric coupling members falls within the range of the misalignment between the polish rod and the box affixed to upstanding casing 20.

Therefore, the embodiment of FIGURE 1 provides a means by which a standard stufling box 14 can be attached to a standard coupling 22 and the polish rod exactly aligned with the sufiing box.

In aligning the apparatus illustrated in FIGURE 1, coupling 22 and the stufiing box 14 are tightened with respect to tubing 20 and coupling member 16, respectively. Eccentric coupling members 16 and 18 are then threaded into their respective members, but leaving an estimated 270 looseness within the threads. This amount of, or lack of tightness, generally will enable the members either to be backed up half a turn, or tightened half a turn, while any position therebetween will alford ample tightness for operation of the assembly.

With the polish rod extending through the assembled device, members 16 and 18 are moved with respect to each other and to the coupling 22 to thereby exactly align the polish rod with the stuffing box 14. Exact alignment is made possible since rotational movement of member 16 with respect to member 18 describes an are dependent upon the amount of eccentricity built into member 16, while rotation of member 18 with respect to coupling 22 describes another arc about the longitudinal central axis of tubing 20.

While the embodiment of FIGURE 1 sets forth means by which conventional stufi'lng boxes 14 may be attached to a conventional coupling 22 by the provision of alignment means 16 and 1-8, to thereby enable stuffing boxes of the prior art to be provided with the alignment means of the instant invention; it is advantageous to eliminate one of the eccentric couplings 16 or 18 by practicing the invention in accordance with the embodiment of FIG- URE 2. As seen in FIGURE 2, a stufiing box 62 is provided with an eccentric at 68 to thereby enable the stuffing box to describe an are about the polish rod which is received within the aperture provided in the packing nut 66. The second eccentric is provided by the eccentric coupling 64, which for all practical purposes is identical to the before described eccentric coupling 16 or 18 of FIGURE 1.

Alignment of the stuffing box 62 with the polish rod is accomplished by relative rotational motion between the eccentric stufiing box 62 and the eccentric coupling 64 along with the position of the box and coupling with respect to the tubing 20'.

The embodiment of FIGURE 4 eliminates still another member, namely the eccentric coupling 64. As seen in FIGURE 4, an eccentric stufling box 80 is provided with eccentricity as indicated at the arrow at numeral 81 and screw-fitted into an eccentrically fabricated coupling 85. Coupling 85 is directly screwed onto the upstanding terminal end of the tubing 20 and rotational motion between the coupling 85, and the stutfing box 80, provides two eccentric paths which may be selectively adjusted to bring the polish rod into perfect alignment with the top of the stufiing box.

FIGURES 5 and 6 illustrate a device which may be temporarily substituted for the apertured nut 24, for example, of FIGURES 1 and 3, to enable rapid and perfect alignment of the stuffing box with the polish rod. Assuming the assembly illustrated in FIGURE 2 to be properly assembled upon a casing 20, and with the polish rod extending longitudinally therethrough, but misaligned with respect to the apertured nut 66. The nut 66 is removed from the eccentric stuffing box 62 and held clear of the assembly. One half of the device, member 93 for example, is fitted into the top of the box 62 with the downwardly depending flange 98 snugly fitted against the inside peripheral wall of the upper terminal end of the box. The eccentric box 62 is rotated with respect to the eccentric coupling 64 and the eccentric coupling 64 is rotated with respect to the coupling 22 until the polish rod is brought into exact alignment with the aperture 97. The other half 94 of the alignment means 92 is then placed on top of the box, in a manner similar to the placement of element 93, and the final alignment of the stuffing box 62 made in accordance with the above description until the polish rod is exactly aligned with the aperture 97 as visually determined by the clearance between the outside peripheral wall surface of the rod and the aperture 97. Members 9 3 and 94 are next removed from the top of the box, injection packing 46 suitable placed within the box, whereupon the box can then be assembled by properly tightening the nut 66 against the packing ring. The box may then be lubricated with a high pressure fitting that is generally included as part of the assembly.

Where it is desired to eliminate the coupling 22', an eccentric coupling may be used in conjunction with an eccentric box 62 or 80, whereupon a multiplicity of components may be eliminated from the assembly.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to.

We claim:

1. In a stuffing box adapted to be connected to the terminal end of an oil well tubing, wherein the box receives a reciprocating polish rod for actuating a downhole pump; the improvement comprising:'

an alignment means for aligning the stufling box with the polish rod, said alignment means comprising;

first eccentric means and second eccentric means connected between the rod receiving end of the box and the tubing;

said first eccentric means including a lower threaded portion with the central axis of the threaded portion being radially offset from the central axis of the rod receiving portion of the box;

said second eccentric means including an upper threaded portion that threadedly engages said lower threaded portion of said first eccentric means and further including a lower threaded portion radially offset from said upper threaded portion of said second eccentric means;

said stutfing box includes an upstanding terminal end portion having a packing nut removably aflixed thereto;

a template having means forming a centrally located aperture of an inside diameter greater than the outside diameter of the polish rod;

21 downwardly depending flange circumferentially disposed near the outer marginal edge portion of said template, with the outside dimension of said flange being received within the inside of the terminal end portion of the box;

said template being divided into two parts by means forming a cut extending along a vertical plane that leaves one template part having at least 1180 of flange circumference.

2. The improvement of claim 1 wherein said lower threaded portion of said first eccentric means includes a lower end portion of said stufling box; and

said second eccentric means threadedly fastens said stufiing' box to the upper terminal end portion of the oil well tubing.

3. The improvement of claim 1 wherein:

said first and second eccentric means for identical in construction;

one said eccentric means having an upper terminal and which includes threads disposed about the inside perip'heral Wall surface thereof to provide said upper threaded portion;

said lower threaded portion of said one said eccentric means including threads disposed about the outer Wall surface thereof and adapted to cooperate with the upper terminal end of the remaining eccentric means, and further adapted to cooperate with the upper terminal end portion of the oil well tubing.

4. The improvement of claim 1, wherein:

said first eccentric means includes said stuffing box, wherein said lower threaded portion comprises means by which the box is attached to the well tubing;

said upper threaded portion of said second eccentric means including a first female portion;

said lower threaded portion of said second eccentric means including a second female portion;

a passageway interconnecting said first and second female portion; whereby:

said box can be directly aflixed to said second eccentric means, and said second eccentric means can be directly aflixed to the well tubing.

5. The improvement of claim 1, wherein:

said first and second eccentric means are identical in construction;

one said eccentric means having an upper terminal end that includes threads disposed about the inside peripheral wall surface thereof to provide said upper threaded portion;

said lower threaded portion including threads disposed about the outer wall surface thereof and adapted to cooperate with the upper terminal end of the re maining eccentric means, and further adapted to cooperate with the upper terminal end portion of the oil well tubing;

said upper and lower threaded portions being joined by a passageway having a diameter equal to the rod diameter in addition to the amount of eccentricity provided by the first and second eccentric means;

the upper and lower portion of said one eccentric means having a thickened Wall member in the direction of the eccentricity to thereby provide for the recited threaded portions.

6. In combination with a stufiing box wherein the box is adapted to be connected to a terminal end of an oil well tubing, and wherein the box is adapted to slidably receive a reciprocating polish rod therethrough, a template for aligning the rod with the box, said template having means forming a centrally located aperture of an inside diameter which is greater than the outside diameter of the polish rod;

a downwardly depending flange circumferenti'ally disposed near the outer marginal edge portion of said template, with the outside dimension of said flange being received Within the inside of the terminal end portion of the box;

said template being divided into two members by means forming a cut which leaves one template member having at least 180 of flange circumference.

7. The combination of claim 6, and further including an outwardly depending marginal edge portion circumferentially disposed about said downwardly depending flange, said outwardly depending marginal edge portion adapted to be seated on an uppermost portion of the box.

8. The combination of claim 6, wherein said means forming a cut is a vertical plane relative to the flange and said cut leaves one template part having a flange circumference of more than 180 and less than 270.

References Cited FOREIGN PATENTS 1913 Great Britain. 1/1961 Germany.

US. Cl. X.R. 285-27 

